Definitely worth of a day trip is a coastline between Karterados Beach and Vourvoulos Port/Beach.
How to get there: Start your trip at Karterados Beach. Get there with your ATV or with a car, from Caveland it will take you about 5 minutes. Just head down to the beach under the hostel, park your vehicle on the beach and start the beach day on the north-east coast of Santorini.
When to go: Make sure you will set off early enough. This coastline has high rock and sand formations around which means that around 6pm there is not much sun. You are on the east coast of the island, so the sun rises here!
Karterados Beach is a nice black sand beach. It is not an organized beach, that is the reason you might find yourself here alone or just with few people. There is a nice tavern right on the beach, good for a small snack.
Between Karterados and Exo Gialos you will see splendid rock and sand formations, the beach is worthy to spend your time as well- it is sandy and black and not many people go there!
Exo Gialos is a small port, about 20 minutes walk along coastline from Karterados beach. There is a small port and a tavern with a changing cabins and a toilette. Cool place to grab a bear!
Kanakari is the next beach. It is named after Kanakari family who owned today closed tomato factory here. The beach is with small pebbles and black sand. With a good weather you will see from here an opposite island Anafi. Santorini has 300+ churches and chapels and one of them is also here, overlooking the sea!
Vourvoulos Port and a beach is your next stop, about 30 minutes walk from Kanakari. Be ready to walk on a beach made of stones. In Vourvoulos you will find a small fish tavern, few fisherman boats and a nice black-sand beach. During the main season there is also a volley-ball net worthy to use! More really amazing rock and sand formations and small caves!